Fans of the cross-flow type



Feb. 21, 1967 N. LAING 3,305,164

FANS OF THE CROSS-FLOW TYPE Original Filed Nov. 17, 1959 2 Sheets-Sheet1 FIG].

ATTORNEYS FANS OF THE CROSS-FLOW TYPE Original Filed Nov. 17, 1959 2Sheets-Sheet 2 FIG .2.

Zia 2/ P4 244 ZflZ 220 22/ 222 M; o 2 I 222/ 4 0o 25/ 22/ 'INVENTOR 202NIKOLAUS LAING BY/j ifiz Z ATTORNEYS United States Patent 3,305,164 FANSOF THE CROSS-FLOW TYPE Nikolaus Laing, Stuttgart, Germany, assignor, bymesne assignments, to Laing Vortex, Inc., New York, N.Y. Originalapplication Nov. 17, 1959, Ser. No. 853,596.

Divided and this application Aug. 17, 1965, Ser.

16 Claims. (Cl. 230-117) This invention relates to fans of thecross-flow type. The application is a division of my copendingapplication Serial No. 853,596, filed Nov. 17, 1959.

The invention more particularly concerns fans of the cross-flow type,that is, machines comprising a cylindrical bladed rotor mounted forrotation about its axis in a predetermined direction and defining aninterior space, and guide means defining with the rotor an entry regionand a discharge region, the guide means and rotor cooperating onrotation of the latter in said predetermined direction to induce a flowof air from the entry region through the path of the rotating blades ofthe rotor to said interior space and thence again through the path ofsaid rotating blades to the discharge region. More especially but notexclusively, the invention concerns fans of the cross-flow type whereinthe guide means and rotor co-operate to set up a vortex of Rankincharacter having a core region eccentric of the rotor axis and a fieldregion which guides the air so that flow through the rotor is stronglycurved about the vortex core: such fans are sometimes known astangential fans and the preferred from of fan to be described in detaillater is of this type.

Cross-flow fans have in recent years become of great and increasingtechnical and commercial importance, and it is being appreciated thatsuch fans can advantageously be used in a wide range of apparatus.

One main object of the invention is to provide a crossfiow fan unitwhich can be simply and cheaply produced in quantity and which iscompact and can readily be built into different forms of apparatus.

With this object in view the invention provides a fan unit comprising amotor having a drive shaft and a pair of bladed cylindrical rotors oneon either side of the motor and each having one end mounted on thecorresponding end of the motor drive shaft. If the unit has only to berelatively short the rotors can be overhung on the shaft ends; longerrotors could be supported at their ends opposite the motor. Guide meansare provided to co-operate with the rotors in the manner describedabove. These guide means comprise at least one guide wall secured to themotor and extending parallel to the axis of the rotors over the wholedistance between the extreme ends of the rotors. This guide wall forms amain structural member for the unit and avoids the need for a separateframe or structure to interconnect the guide means for the two rotorsand to position such means relative to the rotors.

Preferably, the guide means for the two rotors comprises two guide wallsboth extending the whole distance between the extreme ends of the rotorsand interconnected by outer end walls in general alignment with suchextreme ends of the rotor. This provides a box-sinder-like constructionwhich will have the required rigidity even if constructed out of, say,relatively thin sheet metal. Inner end walls, substantially aligned withthe ends of the rotors adjacent the motor, may provide the means forsecuring the guide walls to the motor: such inner end Walls have afurther rigidifying effect on the guide structure.

According to a further important feature of the invention the guidewalls and outer ends walls preferably define a common discharge regionreceiving flow from both rotors and delivering an air flow which iscontinuous over the length of the unit. This feature avoids the drawbackof single-rotor constructions, that if the motor and rotor occupy agiven length, air flow only occurs over the part of the total lengthoccupied by the rotor and not over the length of the motor. Theinvention provides means to promote flow over the central zone of thecommon discharge region, so as to help even out the flow over the totallength.

Further features of the invention, together with objects and advantagesthereof, will become apparent from the following description of oneembodiment thereof, including certain varients of this embodiment, whichdescription is given purely by way of example, and with reference to theaccompanying diagrammatic drawings in which:

FIGURE 1 is a perspective View of a sub-unit for a fan heater;

FIGURE 2 is a vertical longitudinal section of the sub-unit shown inFIGURE 1;

FIGURE 3 is a horizontal longitudinal section of the central part ofsub-unit of FIGURE 1 showing variant motor cooling arrangements; and

FIGURE 4 is a vertical transverse section of the subunit of FIGURES 1and 2 taken on the line aa of FIGURE 2;

FIGURES 1 to 4 show a sub-unit incorporating a casing, for example toform a fan heater, the casing having appropriately located inlet andoutlet for the air flow.

The sub-unit comprises first and second guide walls 201, 202 securedbetween substantially plane parallel outer end walls 203, 204. A pair ofintermediate or inner walls 205, 206 are arranged symmetrically betweenand parallel to the end walls 203, 204 and secured to the guide walls.The intermediate walls 205, 206 mount between them a motor 207, theshaft 208 of which projects to either side to mount a pair of similarbladed cylindrical rotors 209, 210. The rotors 209, 210 each comprise aseries of blades 210' mounted parallel to the axis of rotation and in aring thereabout between end support discs 211, 212, the discs 211adjacent the intermediate walls 205, 206 being received in recesses inthose walls and formed with integral bosses 213 push-fitted on the endportions of the motor shaft 208.

The left and right hand sides of FIGURE 2 show variant constructions ofthe end walls 203, 204. In each case, the corresponding rotor end disc212 closely overlies the end wall, but at the right hand side of thefigure the disc 212 is shown received in a recess in the end wall 204,which may be formed as a sheet metal pressing. At the left hand side ofthe figure the end wall 203 is shown without a recess, but with acentral projection 214 received with clearance in a central hole 215 inthe end disc 212 of the rotor 209. In normal operation the projection214 has no effect, but if the sub-unit is dropped, for example, itengages the side of the hole 215 so as to prevent the rotor end disc 211from being stressed beyond its elastic limit, as would permanentlydamage the sub-unit. The variant constructions are combined in FIGURE 2for economy of illustration. An actual construction would have similarend walls.

The guide wall 201 consists of a main guide portion 220 (see FIGURE 4)and an outlet portion 221: the main guide portion 220 converges with therotors 209, 210 in the direction of rotor rotation (shown by the arrowA) from a rounded nose 222, where it joins the outlet portion 221 at anangle of somewhat over to a line 223 of nearest approach to the rotor.The guide wall 202 diverges from the rotors 209, 210 with steadilyincreasing radius of curvature from a line of nearest approach 224diametrically opposite the line 223. Both these lines of nearestapproach are well spaced from the rotors 209, 210, and at both therespective guide wall is rounded away from the rotors on the side of airentry thereto. The guide walls 201, 202 terminate adjacent their linesof nearest approach to the rotors 209, 210, and define for each rotor anentry region ER (FIGURE 4) on one side of the unit. The rotors 209, 210'have an approximately 180 are projecting free beyond the planecontaining the edges of the guide walls 201, 202 on the inlet side.

The innner 'end walls 205, 206 terminate adjacent the motor 207 on thedownstream side thereof. The outer end walls 203, 204 extend further onthis side than the inner end walls, and they define with the guide walls201, 202 a common discharge region CDR receiving the air from bothrotors 209, 210. The guide walls 201, 202 diverges in the direction offlow so that this common discharge region acts as a diffuser.

On operation of the motor 207 to rotate the rotors 209, 210 in thedirection of the arrow A (FIGURE 4) the rotors and the guide walls 201,202 co-operate to set up a vortex of Rankine character having a coreapproximately indicated at V in FIGURE 4 which is eccentric of the axisand consists of a region of circulatory flow interpenetrating the rotorblades 210' adjacent the portion 220 of the guide wall 201. The vortexfurther comprises a field region wherein air is induced to flow througheach rotor 209, 210 from its entry region ER through the path of therotating blades of the rotor to the interior thereof and thence againthrough the path of the rotating blades to the common discharge regionCDR. The flow pattern is here shown purely diagrammatically: it is morefully discussed in British Patent 87 6,6l1in which I am coinventor. Inpassing from the entry region ER to the common discharge region CDR thebulk of the throughput is caused to turn around the vortex core Vthrough an angle exceeding 90, but without the losses which would beassociated wit-h bent ducting designed to effect a similar turn.

An electric heater element is located in the common discharge region CDRand comprises coiled resistor wire 230 supported on insulating supportplates 231 secured between the guide walls 201, 202 parallel to the endwalls 203, 204, so as to minimiseresistance to air flow. The plates 231are located approximately opposite the rotor end discs 211, 212 and theresistor wire 230 is arranged to provide greater heating (i.e.dissipation of watts per unit of length parallel to the rotor axis)opposite the rotors 209, 210 than between them, where the air flow isless.

As shown in FIGURE 3 a baffie plate or fairing 235 is secured betweenthe guide walls 201, 202 in the central zone of the common dischargeregion CDR, downstream of the motor 207. The bafile 235 has theapproximate outline in horizontal section of a semicircle with itsupstream ends, in general alignment with, but spaced from, the innerendwalls 205, 206. For economy of illustration in FIGURE 3 variantconstructions of the bafile plate or fairing 235 are shown on oppositesides of the centre line. Thus to the left of the centre line the end ofthe baffle plate or fairing 235 is shown bent slightly to the motor sideof the plane of the end wall 205, While the end on the right hand sideof the line is shown bent slightly to the rotor side of the end wall206. The purpose of the baffle plate or fairing 235 is'two-fold, firstlyto guide air flow from the two rotors 209, 210 towards the central zoneof the common discharge region CDR, and secondly to set up a small flowof cooling air through the motor 207. In the variant construction shownon the left hand side, a flow of cooling air is sucked through themotor, while on the right hand side air which has passed the rotor 210is diverted back through the rotor by the bafile plate or fairing. In agiven construction the baffle plate or fairing 235 would normally besymmetrical, adopting for both sides either one or the other of thevariants described. However, an asymmetrical arrangement, substantiallyas shown, would be a possibility.

Auxiliary baffles 236 are mounted symmetrically between the guide walls201, 202 adjacent the baflle plate or fairing 235 and outside it. Inoperation air is helped to flow around the outside of the baffle plateor fairing 235 by the auxiliary baffles 236. The curved baffle plate orfairmg 235 and auxiliary baflles 236 help to deflect air longitudinallyinto the central zone of the common discharge region between thedownstream rotors 209, 210, and thus tend to even out flow through thisregion as considered over its whole length between the end walls 203,204. The central insulating support plates 231 are shown in FIGURE 3 asspaced somewhat outwardly of the intermediate walls 205, 206.

Where the construction of the baffle plate takes the form as shown inthe left-hand side of FIGURE 3 for both rotors or for a single rotor ina fan unit having only one 'rotor, air will flow over the motor throughslots'240 as shown in FIGURE 1. It is thus seen that the bafileconstruction shown on the left side of FIGURE 3 provides a passagewaywhich extends from the motor compartment to an area adjacent the rotor209 where the pressure is less than ambient such that cooling air iscaused to flow over the motor, into the motor compartment and thence toan area adjacent the rotor.

I claim:

1. A fan unit comprising an electric motor having a drive shaft, a pair.of bladed cylindrical rotors one on either side of the motor and eachdefining an interior space and having one end mounted on thecorresponding end .of the motor drive shaft, and guide means compris=ing a pair of spaced guide walls secured to the motor and extendinggenerally parallel to the axis of the rotors over the whole lengthbetween the extreme ends of the rotors and a pair of outer end wallsjoining the guide walls and in substantial alignment with said extremeends, said guide walls forming a frame for said fan unit, said walls defining an entry region for each rotor at one side of the unit and acommon discharge region at another side of the unit, said guide meansco-operating with the rotors, whereby on operation of the motor toinduce a flow of air from the entry region of each rotor through thepath of the rotating blades thereof to said interior space and thenceagain through the path of the rotating blades to the common dischargeregion. r

2. A fan unit as claimed in claim 1, including a fairing extendingbetween the guide walls on the downstream side of the motor to guide airfrom each rotor towards the central zone of said common dischargeregion.

3. A fan unit as claimed in claim 1, wherein the rotors are overhung onthe ends of the drive shaft.

4. A fan unit as claimed in claim 3, wherein said end walls extend overthe extreme ends of the rotors and carry projections extending intooversize holes in the rotor ends to limit bending of the rotors in caseof abuse of the unit.

5. A fan unit comprising an electric motor having a drive shaft, a pairof bladed cylindrical rotors one on either side of the motor and eachdefining an interior space and having one end mounted on thecorresponding end of the motor drive shaft, and guide means comprising apair of inner end walls fixed to the motor and in substantial alignmentwith the ends of the rotors adjacent thereto, a pair of spaced guidewalls secured to said inner end walls and extending generally parallelto the axis of the rotors over the whole length between the extreme endsof the rotors and a pair of outer end walls joining the guide walls andin substantial alignment with said extreme ends with said guide wallsforming a frame for said fan unit, said walls defining for each rotor anentry region at one side of the unit and a discharge region at anotherside of the unit, said guide means co-operating with the rotors, wherebyon operation of the motor to induce a flow of air from the entry regionof each rotor through the path of the rotating blades thereof to saidinterior space and thence again through the path of the rotating bladesto said discharge region.

6. A fan unit comprising an electric motor having a drive shaft, abladed cylindrical rotor defining an interior space and having one endmounted on the motor shaft,

guide means comprising a pair of spaced guide walls secured to the motorand extending generally parallel to the axis of the rotor, and wallsjoining the guide walls, said guide Walls and end walls definingan'entry region for said rotor and a discharge region for said rotor,said guide means cooperating with the rotor on operation of the motor toinduce flow of air from the entry region of said rotor through the pathof the rotating blades thereof to said interior space and thence againthrough the path of the rotating blades to the discharge region, andbafile means in said discharge region to divert a proportion of theoutlet flow through the motor for cooling thereof.

7. A fan unit comprising an electric motor positioned in a motorcompartment and having a drive shaft, a bladed cylindrical rotordefining an interior space and having one end mounted on the motor driveshaft, guide means comprising a pair of spaced guide walls secured tothe motor and extending generally parallel to the axis of the rotor; apair of end walls joining the guide walls, said guide walls and said endwalls defining an entry region for said rotor at one side of said unitand a discharge region for said rotor at another side of said unit, saidguide means cooperating with the rotor on operation of the motor toinduce a flow of air from the entry region of the rotor through the pathof the rotating blades thereof to said interior space and thence againthrough the path of the rotating blades to the discharge region, and atleast one passageway extending from the motor compartment to a regionadjacent the rotor of lower pressure than ambient whereby cooling airwill flow from said compartment through said passageway and into theregion of lower pressure.

8. A fan unit comprising an electric motor having a drive shaft, a pair.of bladed cylindrical rotors one on either side of the motor and eachdefining an interior space and having one end mounted on thecorresponding end of the motor drive shaft, and guide means comprising apair of spaced guide walls secured to the motor and extending generallyparallel to the axis of the rotors over the whole length between theextreme ends of the rotors and a pair of outer end walls joining theguide walls and insubstantial alignment with said extreme ends, saidwalls defining an entry region for each rotor at one side of the unitand a common discharge region at another side of the unit, said guidemeans co-operating with the rotors, whereby on operation of the motor toinduce a flow of air from the entry region of each rotor through thepath of the rotating blades thereof to said interior space and thenceagain through the path of the rotating blades to the common dischargeregion, and a baffle extending between the guide walls adjacent theinner end of each rotor in said common discharge region to guide airfrom each rotor to the central zone of said region.

9. A fan unit comprising an electric motor having a drive shaft, a pairof bladed cylindrical rotors one on either side of the motor and eachdefining an interior space and having one end mounted .on thecorresponding end of the motor drive shaft, and guide means comprising apair of spaced guide walls secured to the motor and extending generallyparallel to the axis of the rotors over the whole length between theextreme ends of the rotors and a pair of outer end walls joining theguide walls and in substantial alignment with said extreme ends, saidwalls defining an entry region for each rotor at one side of the unitand a common discharge region at another side of the unit, said guidemeans co-operating with the rotors, whereby on operation of the motor toinduce a flow of air from the entry region of each rotor through thepath of the rotating blades thereof to said interior space and thenceagain through the path of the rotating blades to the common dischargeregion, and a batfie means in said common discharge region to divert aproportion of the flow from at least one rotor through the motor forcooling thereof.

10. A fan unit as claimed in claim 9, wherein said bafile means extendsbetween the guide walls and forms a fairing around the downstream sideof the motor to guide air from the rotors to the central zone of thecommon discharge region.

11. A fan unit comprising an electric motor having a drive shaft, a pairof bladed cylindrical rotors one on either side of the motor and eachdefining an interior space and having one end mounted on thecorresponding end of the motor drive shaft, and guide means comprising apair of spaced guide walls secured to the motor and extending generallyparallel to the axis of the rotors over the whole length between theextreme ends of the rotors and a pair of outer end walls joining theguide walls and in substantial alignment with said extreme ends, saidwalls defining an entry region for each rotor at one side of the unitand a common discharge region at another side of the unit, said guidemeans co-operating with the rotors, whereby on operation of the motor toinduce a fiow of air from the entry region of each rotor through thepath of the rotating blades thereof to said interior space and thenceagain through the path of the rotating blades to the common dischargeregion, and a bafile means in said common discharge region whereby flowtherein induces into said region a flow of cooling air through themotor.

12. A fan unit as claimed in claim 11, wherein said baffie means extendsbetween the guide walls and forms a fairing around the downstream sideof the motor to guide air from the rotors to the central zone of thecommon discharge region.

13. A fan unit comprising an electric motor having a drive shaft, a pairof bladed cylindrical rotors one on either side of the motor and eachdefining an interior space and having one end mounted on thecorresponding end of the motor drive shaft, and guide means comprising apair of inner end walls fixed to the motor and in substantial alignmentwith the ends of the rotors adjacent thereto, a pair of spaced guidewalls secured to said inner end walls and extending generally parallelto the axis of the rotors over the whole length between the extreme endsof the rotors and a pair of outer end walls joining the guide walls andin substantial alignment with said extreme ends, said Walls defining foreach rotor an entry region at one side of the unit and a dischargeregion at another side of the unit, said guide means co-operating withthe rotors, whereby on operation of the motor to induce a flow of airfrom the entry region of each rotor through the path of the rotatingblades thereof to said interior space and thence again through the pathof the rotating blades to said discharge region, said inner end wallsterminating short of the other walls so that said discharge regions forthe two rotors merge and discharge takes place over the whole lengthbetween the outer end walls.

14. A fan unit as claimed in claim 13 including a balfie extendingbetween the guide walls around the downstream side of the motor to guideair from each rotor to discharge in the central zone between said outerend walls, the bafile having its ends in general alignment with theinner end walls.

15. A fan unit as claimed in claim 14 wherein the upstream ends of thebafile are spaced from the downstream ends of the inner end walls andformed in relation thereto to induce through said spaces a flow ofcooling air over the motor.

16. A fan unit comprising an electric motor having a drive shaft, a pairof bladed cylindrical rotors one on either side of the motor and eachdefining an interior space and having one end mounted on thecorresponding end of the motor drive shaft, and guide means comprising apair of inner end walls fixed to the motor and in substantial alignmentwith the ends of the rotors adjacent thereto, a pair of spaced guidewalls secured to said inner end walls and extending generally parallelto the axis of therotors over the whole length betweenthe extreme endsof the rotors and a pair of outer 'end walls joining the guide walls andin substantial alignment with said extreme ends, said walls defining foreach rotor an entry region at one side of the unit and a dischargeregion at another side of the unit, said guide means co-operating withthe rotors, whereby on operation of the motor to induce a flow of airfrom the entry region of each rotor through the path of the rotatingblades thereof to said interior space and thence again through the pathof the rotating blades to said discharge region, said end walls 15 beingrecessed to receive the ends of the rotors.

References Cited by the Examiner UNITED STATES PATENTS 9/1931 Young230-117 11/ 1932 Anderson 230--125 3/ 1934 Anderson 230-125 6/1940 Euwer230-117 6/1960 Eck 230-125 FOREIGN PATENTS 10/ 1959 Switzerland.

DONLEY I. STOCKING, Primary Examiner.

HENRY F. RADUAZO, Examiner.

1. A FAN UNIT COMPRISING AN ELECTRIC MOTOR HAVING A DRIVE SHAFT, A PAIROF BLADED CYLINDRICAL ROTORS ONE ON EITHER SIDE OF THE MOTOR AND EACHDEFINING AN INTERIOR SPACE AND HAVING ONE END MOUNTED ON THECORRESPONDING END OF THE MOTOR DRIVE SHAFT, AND GUIDE MEANS COMPRISING APAIR OF SPACED GUIDE WALLS SECURED TO THE MOTOR AND EXTENDING GENERALLYPARALLEL TO THE AXIS OF THE ROTORS OVER THE WHOLE LENGTH BETWEEN THEEXTREME ENDS OF THE ROTORS AND A PAIR OF OUTER END WALLS JOINING THEGUIDE WALLS AND IN SUBSTANTIAL ALIGNMENT WITH SAID EXTREME ENDS, SAIDGUIDE WALLS FORMING A FRAME FOR SAID FAN UNIT, SAID WALLS DEFINING ANENTRY REGION FOR EACH ROTOR AT ONE SIDE OF THE UNIT AND A COMMONDISCHARGE REGION AT ANOTHER SIDE OF THE UNIT, SAID GUIDE MEANSCO-OPERATING WITH THE ROTORS,